Question

Which among the following statement is incorrect?

• A. One gram atom of carbon contains avogadro’s number of atoms.
• B. One mole of oxygen gas contains avogadro’s number of atoms.
• C. One mole of hydrogen contains avogadro’s number of atoms.
• D. Mole = Mass / Molecular mass.

Answer 1

Answer: (B)

Explanation:

• One mole atoms of oxygen has a mass of 16 g, as 16 is the atomic weight of oxygen, and contains $6.02\times {10}^{23}$ atoms of oxygen.
• One mole of oxygen gas, which has the formula $O_2$, has a mass of 32 g and contains $6.02\times {10}^{23}$​ molecules of oxygen but $12.04\times {10}^{23}$(i.e. $2\times 6.02\times {10}^{23}$​) atoms because each molecule of oxygen contains two oxygen atoms.

Hence, option (B) is correct.